At the bench: preclinical rationale for CTLA-4 and PD-1 blockade as cancer immunotherapy

Image-Based Phenotypic Screening with Human Primary T Cells Using One-Dimensional Imaging Cytometry with Self-Tuning Statistical-Gating Algorithms

The parallel microfluidic cytometer (PMC) is an imaging flow cytometer that operates on statistical analysis of low-pixel-count, one-dimensional (1D) line scans. It is highly efficient in data collection and operates on suspension cells. In this article, we present a supervised automated pipeline for the PMC that minimizes operator intervention by incorporating multivariate logistic regression for data scoring. We test the self-tuning statistical algorithms in a human primary T-cell activation assay in flow using nuclear factor of activated T cells (NFAT) translocation as a readout and readily achieve an average Z' of 0.55 and strictly standardized mean difference of 13 with standard phorbol myristate acetate/ionomycin induction. To implement the tests, we routinely load 4 µL samples and can readout 3000 to 9000 independent conditions from 15 mL of primary human blood (buffy coat fraction). We conclude that the new technology will support primary-cell protein-localization assays and "on-the-fly" data scoring at a sample throughput of more than 100,000 wells per day and that it is, in principle, consistent with a primary pharmaceutical screen.

Releasing the brake: safety profile of immune check-point inhibitors in non-small cell lung cancer

INTRODUCTION

Immune check-point inhibitors are now employed as single-agents in current practice for the treatment of advanced non-small cell lung cancer (NSCLC), while combinations of different inhibitors are being evaluated in clinical trials. Although the safety profile of these compounds, with particular reference to drugs targeting programmed death protein 1 (PD-1) and its ligand (PD-L1), is generally considered manageable, peculiar, immune-related toxicities may onset. Areas covered: This review focuses on the immune-related adverse events (irAEs) observed during immune check-point blockade in NSCLC and their management. The authors report the incidence of irAEs based on the currently available data involving NSCLC and provide recommendations on the general approach to irAEs, as well as indications for the most relevant site-specific events. Expert opinion: Since irAEs may involve a wide range of organs and systems and are potentially reversible if promptly treated, early diagnosis should always be achieved; this might be particularly challenging when other potential causes of toxicity are suspected, such as infections or concurrent treatments. Finally, drugs active on the PD-1/PD-L1 axis appear to be generally manageable even when they are administered to patients with relevant comorbidities, provided that adequate clinical monitoring is performed.

Modeling Natural Killer Cell Targeted Immunotherapies

Animal models have extensively contributed to our understanding of human immunobiology and to uncover the underlying pathological mechanisms occurring in the development of diseases. However, mouse models do not reproduce the genetic and molecular complexity inherent in human disease conditions. Human immune system (HIS) mouse models that are susceptible to human pathogens and can recapitulate human hematopoiesis and tumor immunobiology provide one means to bridge the interspecies gap. Natural killer cells are the founding member of the innate lymphoid cell family. They exert a rapid and strong immune response against tumor and pathogen-infected cells. Their antitumor features have long been exploited for therapeutic purposes in the context of cancer. In this review, we detail the development of highly immunodeficient mouse strains and the models currently used in cancer research. We summarize the latest improvements in adoptive natural killer (NK) cell therapies and the development of novel NK cell sources. Finally, we discuss the advantages of HIS mice to study the interactions between human NK cells and human cancers and to develop new therapeutic strategies.

Low Antigen Dose in Adjuvant-Based Vaccination Selectively Induces CD4 T Cells with Enhanced Functional Avidity and Protective Efficacy

T cells with high functional avidity can sense and respond to low levels of cognate Ag, a characteristic that is associated with more potent responses against tumors and many infections, including HIV. Although an important determinant of T cell efficacy, it has proven difficult to selectively induce T cells of high functional avidity through vaccination. Attempts to induce high-avidity T cells by low-dose in vivo vaccination failed because this strategy simply gave no response. Instead, selective induction of high-avidity T cells has required in vitro culturing of specific T cells with low Ag concentrations. In this study, we combined low vaccine Ag doses with a novel potent cationic liposomal adjuvant, cationic adjuvant formulation 09, consisting of dimethyldioctadecylammonium liposomes incorporating two immunomodulators (monomycolyl glycerol analog and polyinosinic-polycytidylic acid) that efficiently induces CD4 Th cells, as well as cross-primes CD8 CTL responses. We show that vaccination with low Ag dose selectively primes CD4 T cells of higher functional avidity, whereas CD8 T cell functional avidity was unrelated to vaccine dose in mice. Importantly, CD4 T cells of higher functional avidity induced by low-dose vaccinations showed higher cytokine release per cell and lower inhibitory receptor expression (PD-1, CTLA-4, and the apoptosis-inducing Fas death receptor) compared with their lower-avidity CD4 counterparts. Notably, increased functional CD4 T cell avidity improved antiviral efficacy of CD8 T cells. These data suggest that potent adjuvants, such as cationic adjuvant formulation 09, render low-dose vaccination a feasible and promising approach for generating high-avidity T cells through vaccination.

Viroimmunotherapy for Colorectal Cancer: Clinical Studies

Colorectal cancer is a leading cause of cancer incidence and death. Therapies for those with unresectable or recurrent disease are not considered curative at present. More effective and less toxic therapies are desperately needed. Historically, the immune system was thought to be an enemy to oncolytic viral therapy. Thinking that oncolysis would be the only mechanism for cell death, oncolytic virologists theorized that immune clearance was a detriment to oncolysis. Recent advances in our understanding of the tumor microenvironment, and the interplay of tumor survival and a patient's immune system have called into question our understanding of both arenas. It remains unclear what combination of restrictions or enhancements of innate and/or cell-mediated immunity can yield the highest likelihood of viral efficacy. This article reviews the variety of mechanisms explored for viruses such as immunotherapy for colorectal cancer.

Immune-related ocular toxicities in solid tumor patients treated with immune checkpoint inhibitors: a systematic review

INTRODUCTION

Immune-related ocular toxicities are uncommon but serious adverse events that may be associated with the use of immune checkpoint inhibitors. The objective of this review is to assess the incidence and risk of ocular toxicities which are potentially immune-related and occur with immune checkpoint treatment of solid tumors. Areas covered: PubMed database has been searched till June 2016. Prospective clinical trials reporting the occurrence of immune-related ocular toxicities in solid tumor patients treated with immune checkpoint inhibitors were included. Eleven trials with 4965 participants were included. These studies included one study for ipilimumab and tremelimumab, three studies for nivolumab, five studies for pembrolizumab and one study comparing pembrolizumab to ipilimumab. No atezolizumab studies were included. The most common ocular toxicities reported with these agents included uveitis and dry eyes. Pooled analysis for odds ratio of all-grade immune-related ocular toxicities is 3.40 [95% CI: 1.32-8.71; P = 0.01]. Expert commentary: Despite being uncommon, immune-related ocular toxicities (particularly uveitis and dry eyes) occur with a higher frequency in cancer patients treated immune checkpoint inhibitors compared to those treated with control regimens.

Harnessing the immune system through programmed death-1 blockade in the management of Hodgkin lymphoma

Immunotherapy is a rapidly evolving therapeutic option in the treatment of lymphoma. Neoplastic cells evade immune recognition through the programmed death (PD)-1/PD-ligand immune checkpoint pathway. Several novel agents have been developed to restore the immune system's ability to recognize and destroy cancer cells. Nivolumab and pembrolizumab are two anti-PD-1 antibodies that have demonstrated success in the treatment of refractory Hodgkin lymphoma. Harnessing the immune system's ability to target neoplastic cells, ideally without the use of cytotoxic chemotherapeutic agents, is one way in which these novel agents are changing the therapeutic landscape in the treatment of lymphomas. Here, we review the emerging data regarding checkpoint inhibitors in the management of Hodgkin lymphoma, the unique adverse effects encountered with the use of these agents, and a practical approach to the management of these adverse effects. Additionally, we discuss upcoming trials that will further assess the promising future developments of checkpoint inhibition in the treatment of not only Hodgkin lymphoma but also other B cell lymphomas and myeloma. These agents offer immense promise of a future where many lymphomas can be treated without the toxic effects of chemotherapeutic agents.

Immune-Related Adverse Events Associated with Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs), including antibodies targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein-1 (PD-1), have shown durable treatment responses in multiple tumor types by enhancing antitumor immunity. However, removal of self-tolerance can induce autoimmunity and produce a unique immune-driven toxicity profile, termed immune-related adverse events (irAEs). As ICIs gain approval for a growing number of indications, it is imperative clinicians increase their knowledge of and ability to manage irAEs. This review examines the etiology, presentation, kinetics, and treatment of irAEs and aims to provide practical guidance for clinicians.

Immune Checkpoint Inhibitors: Therapeutic Tools for Breast Cancer

Breast cancer is one of the major threats to female health, and its incidence is rapidly increasing in many countries. Currently, breast cancer is treated with surgery, followed by chemotherapy or radiation therapy, or both. However, a substantial proportion of breast cancer patients might have a risk for local relapse that leads to recurrence of their disease and/or metastatic breast cancer. Therefore searching for new and potential strategies for breast cancer treatment remains necessary. Immunotherapy is an attractive and promising approach that can exploit the ability of the immune system to identify and destroy tumors and thus prevent recurrence and metastatic lesions. The most promising and attractive approach of immunotherapeutic research in cancer is the blockade of immune checkpoints. In this review, we discuss the potential of certain inhibitors of immune checkpoints, such as antibodies targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed death 1 (PD-1) and lymphocyte activation gene-3 (LAG-3), in breast cancer therapeutics. Immune checkpoint inhibitors may represent future standards of care for breast cancer as monotherapy or combined with standard therapies.

T cell exhaustion: from pathophysiological basics to tumor immunotherapy

The immune system is capable of distinguishing between danger- and non-danger signals, thus inducing either an appropriate immune response against pathogens and cancer or inducing self-tolerance to avoid autoimmunity and immunopathology. One of the mechanisms that have evolved to prevent destruction by the immune system, is to functionally silence effector T cells, termed T cell exhaustion, which is also exploited by viruses and cancers for immune escape In this review, we discuss some of the phenotypic markers associated with T cell exhaustion and we summarize current strategies to reinvigorate exhausted T cells by blocking these surface marker using monoclonal antibodies.

PD-1/PD-L1 blockade in renal cell cancer

INTRODUCTION

Immunotherapy using checkpoint inhibitors is providing significant benefit to patients with renal cell carcinoma (RCC), both in overall survival and tolerability of treatment. Given the recent approval of the first checkpoint inhibitor in RCC, this review discusses the background and clinical data for checkpoint inhibition in RCC. Areas covered: This review introduces and discusses the basic biologic mechanisms of checkpoint inhibitor function and focuses on the current evidence in clinical trials for the use of immunotherapy in RCC. Expert commentary: Immunotherapy has been a mainstay of therapy in RCC, but the recent approval of nivolumab with ORR of 25% and durable responses has provided a transformative new therapeutic option.

The emerging role of immune checkpoint inhibition in malignant lymphoma

To evade elimination by the host immune system, tumor cells commonly exploit physiological immune checkpoint pathways, restraining efficient anti-tumor immune cell function. Growing understanding of the complex dialog between tumor cells and their microenvironment contributed to the development of immune checkpoint inhibitors. This innovative strategy has demonstrated paradigm-shifting clinical activity in various malignancies. Antibodies targeting programmed death 1 and cytotoxic T-lymphocyte-associated protein-4 are also being investigated in lymphoid malignancies with varying levels of activity and a favorable toxicity profile. To date, evaluated only in the setting of relapsed or refractory disease, anti-programmed death 1 antibodies such as nivolumab and pembrolizumab show encouraging response rates particularly in classical Hodgkin lymphoma but also in follicular lymphoma and diffuse-large B-cell lymphoma. As the first immune checkpoint inhibitor in lymphoma, nivolumab was approved for the treatment of relapsed or refractory classical Hodgkin lymphoma by the Food and Drug Administration in May 2016. In this review, we assess the role of the pathways involved and potential rationale of checkpoint inhibition in various lymphoid malignancies. In addition to data from current clinical trials, immune-related side effects, potential limitations and future perspectives including promising combinatory approaches with immune checkpoint inhibition are discussed.

Chemoradiation Increases PD-L1 Expression in Certain Melanoma and Glioblastoma Cells

Immunotherapy approaches currently make their way into the clinics to improve the outcome of standard radiochemotherapy (RCT). The programed cell death receptor ligand 1 (PD-L1) is one possible target that, upon blockade, allows T cell-dependent antitumor immune responses to be executed. To date, it is unclear which RCT protocol and which fractionation scheme leads to increased PD-L1 expression and thereby renders blockade of this immune suppressive pathway reasonable. We therefore investigated the impact of radiotherapy (RT), chemotherapy (CT), and RCT on PD-L1 surface expression on tumor cells of tumor entities with differing somatic mutation prevalence. Murine melanoma (B16-F10), glioblastoma (GL261-luc2), and colorectal (CT26) tumor cells were treated with dacarbazine, temozolomide, and a combination of irinotecan, oxaliplatin, and fluorouracil, respectively. Additionally, they were irradiated with a single dose [10 Gray (Gy)] or hypo-fractionated (2 × 5 Gy), respectively, norm-fractionated (5 × 2 Gy) radiation protocols were used. PD-L1 surface and intracellular interferon (IFN)-gamma expression was measured by flow cytometry, and IL-6 release was determined by ELISA. Furthermore, tumor cell death was monitored by AnnexinV-FITC/7-AAD staining. For first in vivo analyses, the B16-F10 mouse melanoma model was chosen. In B16-F10 and GL261-luc2 cells, particularly norm-fractionated and hypo-fractionated radiation led to a significant increase of surface PD-L1, which could not be observed in CT26 cells. Furthermore, PD-L1 expression is more pronounced on vital tumor cells and goes along with increased levels of IFN-gamma in the tumor cells. In melanoma cells CT was the main trigger for IL-6 release, while in glioblastoma cells it was norm-fractionated RT. In vivo, fractionated RT only in combination with dacarbazine induced PD-L1 expression on melanoma cells. Our results suggest a tumor cell-mediated upregulation of PD-L1 expression following in particular chemoradiation that is not only dependent on the somatic mutation prevalence of the tumor entity.

A Novel PD-L1-targeting Antagonistic DNA Aptamer With Antitumor Effects

The PD-1/PD-L1 axis is a major pathway involved in tumor immune evasion. Here, we report the novel PD-L1 antagonizing DNA aptamer (aptPD-L1) and demonstrate an integrated pipeline that expedites therapeutic aptamer development. Aptamer can exert antibody-mimic functions and is advantageous over antibody for its chemically synthetic nature, low immunogenicity, and efficient tissue penetration. Our results showed that aptPD-L1 blocked the binding between human PD-1 and PD-L1. Experiments using murine models showed that aptPD-L1 promoted in vitro lymphocyte proliferation and suppressed in vivo tumor growth without the induction of observable liver or renal toxicity. Analyses on the aptPD-L1-treated tumors further revealed elevated levels of infiltrating CD4⁺ and CD8⁺ T cells, intratumoral IL-2, TNF-α, interferon (IFN)-γ and the C-X-C motif chemokines, CXCL9 and CXCL10. The CD8⁺ T cells in the aptPD-L1-treated tumors had higher CXCR3 expression level compared to the random-sequence oligonucleotides-treated ones. Besides, the length and density of CD31⁺ intratumoral microvessels were significantly decreased in the aptPD-L1 treatment group. Collectively, our data suggested that aptPD-L1 helps T cell function restoration and modifies tumor microenvironment. These chemokines might orchestrate together to attract more T cells into the tumor tissues to form the positive amplification loop against tumor growth, indicating the translational potential of aptPD-L1 in cancer immunotherapy.

Evaluation of efficacy and safety of different pembrolizumab dose/schedules in treatment of non-small-cell lung cancer and melanoma: a systematic review

Aim: Pembrolizumab is a fully humanized anti-PD-1 agent currently approved for the treatment of advanced melanoma and pretreated non-small-cell lung cancer (NSCLC). Objective: To assess the efficacy and safety of different dose schedules of pembrolizumab in the treatment of patients with advanced NSCLC and melanoma. Search method: MEDLINE database has been searched. Reference lists of original studies and review articles were checked for other related articles. Selection criteria: Prospective clinical trials reporting the outcomes of more than one dose schedule of pembrolizumab in the treatment of advanced NSCLC and melanoma. Data collection & analysis: The review author extracted information on the outcomes of the study for this review, and presented the results. Main results: Four trials with 3425 patients were included in this systematic review. Pooled analysis for the odds ratio of objective response rate comparing 2 versus 10 mg/kg every 3 weeks in advanced melanoma was 1.03 (95% CI: 0.71–1.49; p = 0.89), while for advanced NSCLC, it was 0.97 (95% CI: 0.66–1.43; p = 0.87). Moreover, odds ratio for selected side effects between the two doses was as follows: rash: 0.83 (95 CI: 0.58–1.18; p = 0.29); vitiligo: 1.27 (95% CI: 0.62–2.61; p = 0.52); diarrhea: 0.94 (95% CI: 0.63–1.42; p = 0.79); hypothyroidism: 0.97 (95% CI: 0.63–1.50; p = 0.90); hepatitis/elevated transaminases: 1.86 (95% CI: 0.91–3.79; p = 0.09); nephritis: 0.88 (95% CI: 0.32–2.44; p = 0.80); pneumonitis: 1.17 (95% CI: 0.62–2.23; p = 0.63). Conclusions: Given the equivalence in efficacy and safety between lower doses and higher doses of pembrolizumab, 2 mg/kg every 3 weeks seems to be an appropriate dose for routine practice in advanced pretreated NSCLC and melanoma.

Predictive biomarkers for programmed death-1/programmed death ligand immune checkpoint inhibitors in nonsmall cell lung cancer

PURPOSE OF REVIEW

Immune checkpoint inhibitors, antiprogrammed death receptor 1 (anti-PD-1)/antiprogrammed death-ligand 1 (anti-PD-L1), are new therapeutic regimens for managing advanced nonsmall cell lung cancer patients, giving an overall response rate of approximately 20% as monotherapy in second-line treatment. The use of predictive biomarkers for identifying patients suitable for these therapies is an important issue not only for making treatment decisions, but also from a medical economic point of view.

RECENT FINDINGS

Among potential predictive biomarker candidates for anti-PD-1/PD-L1 treatments in nonsmall cell lung cancer, the expression of PD-L1 (as determined by immunohistochemistry) is currently the most studied. PD-L1 positivity has been associated with higher response rate to anti-PD-1/PD-L1 therapies. However, several observations suggest that the predictive value of PD-L1 expression is not clear-cut. We review other potential predictive biomarkers, including programmed death-ligand 2, IFN-γ, and genetic signatures.

SUMMARY

Standardized techniques and conditions for evaluating PD-L1 expression (tissue quality and age, percentage positivity threshold, managing heterogeneous and dynamic expression) are critical for establishing the use of this protein as a predictive marker. Care should be also taken when using anti-PD-1/PD-L1 therapies in combination with other therapies, which may impact the predictive value of PD-L1 expression.

Critical Functions of the Lysosome in Cancer Biology

Lysosomes (or lytic bodies) were so named because they contain high levels of hydrolytic enzymes. Lysosome function and dysfunction have been found to play important roles in human disease, including cancer; however, the ways in which lysosomes contribute to tumorigenesis and cancer progression are still being uncovered. Beyond serving as a cellular recycling center, recent evidence suggests that the lysosome is involved in energy homeostasis, generating building blocks for cell growth, mitogenic signaling, priming tissues for angiogenesis and metastasis formation, and activating transcriptional programs. This review examines emerging knowledge of how lysosomal processes contribute to the hallmarks of cancer and highlights vulnerabilities that might be exploited for cancer therapy.

Systemic therapy of metastatic melanoma

For patients with metastatic melanoma, there are currently several effective therapeutic options. The BRAF inhibitors vemurafenib and dabrafenib are characterized by rapid tumor control and high response rates. In combination with one of the two MEK inhibitors trametinib and cobimetinib, they achieve response rates (CR + PR, complete plus partial remissions) of 70%, while delaying the development of treatment resistance, as well as a median overall survival of > 2 years with tolerable side effects. Showing long-term survival rates of approximately 20%, the anti-CTLA-4 antibody ipilimumab is the first substance that has led to a significant prolongation of overall survival in patients with metastatic melanoma. However, delayed treatment response and severe immune-mediated side effects may pose limitations to its therapeutic benefit. Usually well tolerated, anti-PD-1 antibody monotherapy using nivolumab and pembrolizumab has yielded response rates (CR + PR) of up to 45% and one-year survival rates of > 70%. The combination of ipilimumab and nivolumab has shown response rates of up to 58% and a median progression-free survival of > 11 months. While this combination is expected to result in a rapid and long-lasting response, this potential benefit comes at the expense of a high level of toxicity. Strategies for treatment sequencing and treatment combinations are currently being investigated in clinical studies. Overall, the prognosis for patients with metastatic melanoma has significantly improved. With long-term survival a possibility, not only acute but also long-term therapeutic side effects must be taken into account.

Combination or single-agent ipilimumab as immunotherapy of advanced melanoma: a critical review

Aim

A pooled analysis of the efficacy and toxicity of combination immunotherapy versus single-agent ipilimumab in the management of advanced melanoma has been conducted.

Methodology

Eligible studies included randomized controlled studies evaluating ipilimumab-based doublet immunotherapy versus ipilimumab monotherapy for the management of unresectable melanoma.

Results

Nivolumab/ipilimumab combination strategy is associated with a significant improvement in objective response rate (odds ratio: 7.38; 95% CI: 3.71-14.67; p < 0.00001) and progression-free survival (0.42; 95% CI: 0.34-0.52; p < 0.00001) as well as a higher relative risk for high-grade elevated alanine aminotransferase (5.58; 95% CI: 2.28-13.67; p = 0.0002).

Conclusion

This analysis demonstrated that nivolumab/ipilimumab combination is associated with a higher objective response rate and progression-free survival in the management of advanced melanoma.

Surface expression of inhibitory (CTLA-4) and stimulatory (OX40) receptors by CD4+ regulatory T cell subsets circulating in human malaria

Several CD4⁺ T cell subtypes contribute to immune homeostasis in malaria, but the markers that define the main suppressive T cell subsets induced by this infection remain largely unknown. Here we provide a detailed phenotypic characterization of immunoregulatory CD4⁺ T cell populations in uncomplicated human malaria. We found an increased proportion of CD4⁺ T cells expressing CTLA-4, OX40, GITR, TNFRII, and CD69 in acute-phase single-species infections with Plasmodium vivax, Plasmodium falciparum, or both. Such an increase was not proportional to parasite density in P. vivax infections, and did not persist after parasite clearance. Significantly, less than 10% of CD4⁺ T cells expressing these regulatory molecules had the classical T regulatory (Treg) phenotype (CD4⁺CD25⁺CD127^-FoxP3⁺). Two major Treg cell subpopulations, which together accounted for 19-23% of all Treg cells circulating in malaria patients, expressed surface receptors with opposing regulatory functions, either CTLA-4 or OX40. OX40⁺ Treg cells outnumbered their CTLA-4⁺ counterparts (1.8:1) during acute P. vivax infection, while a more balanced ratio (1.3:1) was observed following parasite clearance These data reveal new players in the complex CD4⁺ Treg cell network that maintains immune homeostasis in malaria and suggest potential targets for therapeutic interventions to improve parasite-specific effector immune responses.

The immune system and cancer evasion strategies: therapeutic concepts

The complicated interplay between cancer and the host immune system has been studied for decades. New insights into the human immune system as well as the mechanisms by which tumours evade immune control have led to the new and innovative therapeutic strategies that are considered amongst the medical breakthroughs of the last few years. Here, we will review the current understanding of cancer immunology in general, including immune surveillance and immunoediting, with a detailed look at immune cells (T cells, B cells, natural killer cells, macrophages and dendritic cells), immune checkpoints and regulators, sialic acid-binding immunoglobulin-like lectins (Siglecs) and other mechanisms. We will also present examples of new immune therapies able to reverse immune evasion strategies of tumour cells. Finally, we will focus on therapies that are already used in daily oncological practice such as the blockade of immune checkpoints cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death-1 (PD-1) in patients with metastatic melanoma or advanced lung cancer, or therapies currently being tested in clinical trials such as adoptive T-cell transfer.

Evolving treatments for advanced gastric cancer: appraisal of the survival trend

Introduction and areas covered: We analysed the results of the main clinical studies looking at patients with advanced gastric or esophagogastric junction cancer, in order to differentiate between what is already clinical evidence and what is a promise for the cure of such patients. Thus, achievements from key studies, which had been purposely directed at chemotherapy, molecular target therapies and immunotherapy in both first and second-line setting were analysed. Metronomic chemotherapy, which consists of the administration of continuative low-dose anticancer drugs, was considered also. Expert commentary: It was found that patients included in experimental arms of randomized trials compared with controls have often benefited from a statistically significant extension of overall survival. However, further studies are awaited to bring new drugs into clinical practice and to validate candidate biomarkers predictive of response.

Silymarin suppressed lung cancer growth in mice via inhibiting myeloid-derived suppressor cells

In this study, we investigated the antitumor activity of Silymarin in a mouse model of colon cancer xenograft of Lewis lung cancer (LLC) cells. Silymarin significantly suppressed tumor growth and induced apoptosis of cells in tumor tissues at a dose of 25 and 50mg/kg. Silymarin treatment enhanced the infiltration and function of CD8(+) T cells. In the meantime, Silymarin decreased the level of IL-10 while elevated the level of IL-2 and IFN-γ in the serum of tumor-bearing mice. Finally, Silymarin reduced the proportion of myeloid-derived suppressor cells (MDSC) in the tumor tissue and also the mRNA expressions of inducible nitric oxide synthases-2 (iNOS2), arginase-1 (Arg-1) and MMP9, which indicated that the function of MDSC in tumor tissues were suppressed. Altogether, our data here showed that Silymarin inhibited the MDSC and promoted the infiltration and function of CD8(+) T cells thus suppressed the growth of LLC xenografts, which provides evidence for the possible use of Silymarin against lung cancer.

Pretreatment Predictors of Response to PegIFN-RBV Therapy in Egyptian Patients with HCV Genotype 4

BACKGROUND

Egypt has the highest prevalence of a difficult to treat chronic hepatitis C virus (HCV), genotype 4. Pretreatment factors could guide individualization of therapy which aids in treatment optimization and interleukin IL28B gene polymorphism has been shown to closely relate to HCV treatment response. Polymorphisms in genes encoding inhibitors of T-cell response, which have role in disease progression as Programmed Cell Death 1 (PD-1), and Cytotoxic T-Lymphocytes Antigen-4 (CTLA-4), could be candidate markers predicting treatment response.

METHODS

This cohort study consisted of 200 chronic HCV genotype 4 infected patients treated with PegIFN α-2a and RBV in 2 hepatology centers. Genotyping of the polymorphisms in the IL28B gene region (rs12979860), PD1.3 (rs11568821) and CTLA-4 (rs231775) was performed on DNA collected from each patient using TaqMan® genotyping assay. Groups were classified according to response into sustained virological responders (SVR), or non-responders (NR). A multivariate logistic regression analysis was used to identify potential markers, host pretreatment clinical and viral predictive factors including viral load, insulin resistance, and alpha fetoprotein (AFP) related to treatment response.

RESULTS

Our results showed that in a multivariate analyses IL28B C/C genotype was the most significant predictor for SVR (OR = 10.86; p<0.0001) followed by AFP (OR = 0.915; p = 0.001) then CTLA-4/G genotypes (OR = 1.948; p = 0.022). However, PD-1.3/A genotypes and platelets count were significantly related to response in univariate analysis only (OR = 1.973; p = 0.023; OR = 1.007; p = 0.009 respectively).

CONCLUSION

IL28B SNP, AFP level, and CTLA-4 SNP could be used in conjunction to predict treatment response in HCV genotype 4 infected Egyptian patients.

The role of blinatumomab in patients with relapsed/refractory acute lymphoblastic leukemia

Adults with relapsed/refractory B-acute lymphoblastic leukemia (ALL) have a complete remission (CR) rate of 20-45% and median overall survival of 3-9 months, depending on the duration of the first remission and number of lines of salvage therapy. Allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative option for adult patients with relapsed/refractory ALL, and achievement of CR is a crucial step before alloHSCT. Blinatumomab is a bispecific T-cell engager (BiTE®) antibody construct with dual specificity for CD19 and CD3, simultaneously binding CD3-positive cytotoxic T cells and CD19-positive B cells, resulting in T-cell-mediated serial lysis of normal and malignant B cells. It recently gained accelerated approval by the US Food and Drug Administration (FDA) for the treatment of relapsed/refractory Philadelphia chromosome-negative ALL, based on a large phase II trial of 189 adults with relapsed/refractory B-ALL, which showed a CR/CRh (CR with partial hematologic recovery) of 43% after two cycles of treatment. Toxicities include cytokine-release syndrome (CRS) and neurologic events (encephalopathy, aphasia, and seizure). CRS can be alleviated by step-up dosing and dexamethasone, without affecting the cytotoxic effect of blinatumomab. The cause of neurologic toxicity is unclear but is also observed with other T-cell therapies and may relate to variable expression of CD19 within the brain. This review encompasses the preclinical rationale of using the BITE® class of compounds (blinatumomab being the only one that is FDA approved), with clinical data using blinatumomab in the relapsed/refractory setting (pediatrics and adults), the minimal residual disease setting (adults), as well as Philadelphia chromosome-positive ALL. The review also examines the main adverse events: their prevention, recognition, and management; possible mechanisms of resistance; causes of relapse. It also summarizes future trials evaluating the drug earlier in the treatment course to improve activity.

Chimeric Antigen Receptor T-Cell Therapy for the Community Oncologist

: The field of cancer immunotherapy has rapidly progressed in the past decade as several therapeutic modalities have entered into the clinic. One such immunotherapy that has shown promise in the treatment of cancer is the use of chimeric antigen receptor (CAR)-modified T lymphocytes. CARs are engineered receptors constructed from antigen recognition regions of antibodies fused to T-cell signaling and costimulatory domains that can be used to reprogram a patient's T cells to specifically target tumor cells. CAR T-cell therapy has demonstrated sustained complete responses for some patients with advanced leukemia, and a number of CAR therapies are being evaluated in clinical studies. CAR T-cell therapy-associated toxicities, including cytokine release syndrome, macrophage activation syndrome, and tumor lysis syndrome, have been observed and effectively managed in the clinic. In patients with significant clinical responses, sustained B-cell aplasia has also been observed and is a marker of CAR T-cell persistence that might provide long-term disease control. Education on CAR T-cell therapy efficacy and safety management is critical for clinicians and patients who are considering this novel type of treatment. In the present report, the current landscape of CAR T-cell therapy, the effective management of patients undergoing treatment, and which patients are the most suitable candidates for current trials are discussed.

IMPLICATIONS FOR PRACTICE

The present report describes the current status of chimeric antigen receptor (CAR) T lymphocytes as an immunotherapy for patients with relapsed or refractory B-cell malignancies. CAR T cells targeting CD19, a protein expressed on many B-cell malignancies, typically induce high complete response rates in patients with B-cell leukemia or lymphoma who have very limited therapeutic options. Recent clinical trial results of CD19 CAR T-cell therapies and the management of CAR T-cell-associated adverse events are discussed. The present report will therefore inform physicians regarding the efficacy and safety of CAR T cells as a therapy for B-cell malignancies.

PD-1/PD-L1 expression in non-small-cell lung cancer and its correlation with EGFR/KRAS mutations

This study was aimed to detect the correlation among EGFR/KRAS status and PD-1/PD-L1 expression in non-small-cell lung cancer (NSCLC) patients. PD-1 and PD-L1 expressions were detected by immunohistochemistry in 100 surgically resected lung adenocarcinoma tissues and were statistically correlated with clinicopathological characteristics including EGFR and KRAS statuses. Besides, the overall survival (OS) times were analyzed. There was a statistical significances between PD-1 expression in tumor and KRAS status (P = 0.043), with a higher mutation rate in with lower PD-1 expression patients. There was a statistical significance between PD-L1 expression in tumor and EGFR status (P = 0.012), with a higher mutation rate in patients with lower PD-L1 expression. The OS of patients with EGFR mutation was significantly longer than those without EGFR mutation. The OS of patients with lower PD-L1 in tumor was significantly longer than those with higher PD-L1 expression. We found negative associations between PD-L1 expression in tumor and mutated EGFR status, as well as between PD-1 expression in tumor and mutated KRAS status.

Correlation between PD-L1 expression and outcome of NSCLC patients treated with anti-PD-1/PD-L1 agents: A meta-analysis

BACKGROUND

A meta analysis of the correlation between PD-L1 levels and outcomes of PD-1/PD-L1 inhibitors in advanced non small cell lung cancer (NSCLC) has been performed.

METHODS

Eligible studies included those evaluating PD-1/PD-L1 inhibitors in advanced NSCLC and correlating the outcomes to PD-L1 levels.

RESULTS

The search strategy yielded 250 potentially relevant citations from searched databases. After preclusion of ineligible studies, 12 studies were included. Comparing PD-1/PD-L1 inhibitors to docetaxel in second line treatment, the pooled hazard ratio (HR) for progression free survival (PFS) and overall survival (OS) was 0.75 (95% CI 0.62-0.90; p=0.002) and 0.61 (95% CI 0.50-75; p=0.00001) respectively; while the pooled odds ratio (OR) for objective response rate (ORR) was 1.98 (95% CI 1.28-3.07; p=0.002) in the PD-L1>1% population. Moreover, for PD-L1>1% patients versus PD-L1<1% patients treated with PD-1/PD-L1 targeted agents, the OR of ORR was 2.18 (95% CI 1.45-3.29; p=0.0002); while for PD-L1>5% patients versus PD-L1<5% patients, it was 2.66 (95% CI 1.74-4.07; p<0.00001); and for PD-L1>10% versus PD-L1<10% patients, it was 3.38 (95% CI 2.23-5.13; p<0.00001); and for PD-L1>50% versus PD-L1<50% patients, it was 3.99 (95% CI 2.81-5.66; p<0.00001).

CONCLUSIONS

The current analysis of data indicates that the benefit from PD-1 inhibitors versus docetaxel in second line treatment of NSCLC is limited to the PD-L1>1% subpopulation. Moreover, a possible dose effect relationship between the intensity of PD-L1 staining and the potential benefit from PD-1/PD-L1 targeted agents does exist with higher intensity associated with higher ORR.

Risk of pneumonitis in cancer patients treated with immune checkpoint inhibitors: a meta-analysis

BACKGROUND

A meta-analysis of the risk of pneumonitis associated with the use of immune checkpoint inhibitors in cancer patients has been conducted.

METHODS

Eligible publications included randomized trials of cancer patients on immune checkpoint inhibitors, describing events of all-grade and high-grade pneumonitis.

RESULTS

After exclusion of noneligible citations, a total of 11 clinical trials were eligible for the meta-analysis. The odds ratio was 3.96 [95% confidence interval (CI): 2.02-7.79; p < 0.0001] for all-grade pneumonitis and 2.87 (95% CI: 0.90-9.20; p = 0.08) for high-grade pneumonitis. Moreover, the odds ratio of all-grade pneumonitis with a nivolumab/ipilimumab combination versus ipilimumab monotherapy was 3.68 (95% CI: 1.59-8.50; p = 0.002) and, for high-grade pneumonitis, it was 1.86(95% CI: 0.36-9.53; p = 0.46). Subgroup analysis did not reveal a difference between lung cancer patients and other cancer patients in the risk of pneumonitis.

CONCLUSIONS

Our analysis provided evidence that the use of immune checkpoint inhibitors is associated with an increased risk of all-grade pneumonitis compared with chemotherapy or placebo controls.

Risk of endocrine complications in cancer patients treated with immune check point inhibitors: a meta-analysis

BACKGROUND

We performed a meta-analysis of the risk of endocrine adverse events associated with immune check point inhibitors.

METHODS

Eligible studies included randomized trials of cancer patients on immune checkpoint inhibitors; describing events of hypothyroidism, hyperthyroidism, hypophysitis and adrenal insufficiency.

RESULTS

A total of ten clinical trials were eligible for the meta-analysis. The relative risk of all-grade hypothyroidism, hyperthyroidism, hypophyisitis and adrenal insufficiency were 8.26 (95% CI: 4.67-14.62; p < 0.00001), 5.48 (95% CI: 1.33-22.53; p = 0.02); 22.03 (95% CI: 8.52-56.94; p < 0.00001), 3.87 (95% CI: 1.12-13.41; p = 0.03), respectively.

CONCLUSION

Our meta-analysis has demonstrated that the use of immune check point inhibitors is associated with an increased risk of hypothyroidism, hyperthyroidism, hypophysitis and adrenal insufficiency compared with control.

Programmed Death Ligand-1 Immunohistochemistry— A New Challenge for Pathologists: A Perspective From Members of the Pulmonary Pathology Society

The binding of programmed death ligand-1 and ligand-2 (PD-L1 and PD-L2) to PD-1 blocks T-cell–mediated immune response to tumor. Antibodies that target programmed death receptor-1 (PD-1) will block the ligand-receptor interface, thereby allowing T cells to attack the tumor and increase antitumor immune response. In clinical trials, PD-1 inhibitors have been associated with an approximately 20% overall response rate in unselected patients with non–small cell lung cancer, with sustained tumor response in a subset of patients treated by these immune checkpoint inhibitors. Facing a proliferation of PD-L1 immunohistochemistry clones, staining platforms, and scoring criteria, the pathologist must decide on the feasibility of introducing a newly approved companion diagnostic assay that may require purchase not only of a specific antibody kit but of a particular staining platform. Given the likely reality that clinical practice may, in the near future, demand access to 4 different PD-L1 antibodies coupled with different immunohistochemistry platforms, laboratories will be challenged with deciding among this variety of testing methods, each with its own potential benefits. Another immediate challenge to PD-L1 testing in lung cancer patients is that of access to adequate tumor tissue, given that non–small cell lung cancer samples are often extremely limited in size. With PD-L1 testing it has become clear that the historically used US regulatory approach of one assay–one drug will not be sustainable. One evolving concept is that of complementary diagnostics, a novel regulatory pathway initiated by the US Food and Drug Administration, which is distinct from companion diagnostics in that it may present additional flexibility. Although pathologists need to face the practical reality that oncologists will be asking regularly for the PD-L1 immunohistochemistry status of their patients' tumors, we should also keep in mind that there may be room for improvement of biomarkers for immunotherapy response. The field is rich with opportunities for investigation into biomarkers of immunotherapy response, particularly in the form of collaborative, multidisciplinary studies that incorporate oncologists, pathologists, and basic scientists. Pathologists must take the lead in the rational incorporation of these biomarkers into clinical practice.

Augmentation of Immune Checkpoint Cancer Immunotherapy with IL18

PURPOSE

Recent clinical trials and animal models demonstrated that immune checkpoint blockade enhanced effector cell responses and tumor rejection; however, further development and improvement of cancer immunotherapy is necessary for more favorable objective responses. In this study, we examined the effect of IL18 on the antitumor effect of immune checkpoint inhibitors.

EXPERIMENTAL DESIGN

We examined the effect of IL18 on the peritoneal dissemination of CT-26 cells or tail vein injection metastasis of B16/F10 cells using antiprogrammed death-1 ligand-1 (αPD-L1) and/or anti-CTL-associated antigen-4 (αCTLA-4) mAbs.

RESULT

Massive ascites developed after intraperitoneal inoculation of CT-26, resulting in animal death within 30 days. Treatment of mice with αPD-L1 and/or αCTLA-4 significantly prolonged their survival, and a combination of the antibodies and IL18 provided a much greater therapeutic benefit. The combination modality led to the accumulation of precursor of mature natural killer (pre-mNK) cells in the peritoneal cavity together with increased CD8(+) T and decreased CD4(+)CD25(+)Foxp3(+) T cells. Depletion of the pre-mNK cells abrogated the therapeutic effects and increased the number of CD4(+)CD25(+)Foxp3(+) T cells. The combination treatment also suppressed tail vein injection metastasis of B16/F10 cells.

CONCLUSIONS

The results demonstrated that IL18 enhanced therapeutic effects of immune checkpoint blockade against peritoneal dissemination of carcinoma or tail vein injection metastasis of melanoma through accumulation of pre-mNK cells, memory-type CD8(+) T cells, and suppression of CD4(+)CD25(+)Foxp3(+) T cells. A combination of immune checkpoint inhibitors with IL18 may give a suggestion to the development of next-generation cancer immunotherapy. Clin Cancer Res; 22(12); 2969-80. ©2016 AACR.

Stress, metabolism and cancer: integrated pathways contributing to immune suppression

The potential for immune cells to control cancers has been recognized for many decades, but only recently has real excitement begun to spread through the oncology community following clear evidence that therapeutic blockade of specific immune-suppressive mechanisms is enough to make a real difference in survival for patients with several different advanced cancers. However, impressive and encouraging as these new clinical data are, it is clear that more effort should be devoted toward understanding the full spectrum of factors within cancer patients, which have the potential to block or weaken antitumor activity by immune cells. The goal of this brief review is to highlight recent literature revealing interactive stress and metabolic pathways, particularly those mediated by the sympathetic nervous system, which may conspire to block immune cells from unleashing their full killing potential. There is exciting new information regarding the role of neurogenesis by tumors and adrenergic signaling in cancer progression (including metabolic changes associated with cachexia and lipolysis) and in regulation of immune cell function and differentiation. However, much more work is needed to fully understand how the systemic metabolic effects mediated by the brain and nervous system can be targeted for therapeutic efficacy in the setting of immunotherapy and other cancer therapies.

MiR-138 exerts anti-glioma efficacy by targeting immune checkpoints

BACKGROUND

Antibody therapeutic targeting of the immune checkpoints cytotoxic T-lymphocyte-associated molecule 4 (CTLA-4) and programmed cell death 1 (PD-1) has demonstrated marked tumor regression in clinical trials. MicroRNAs (miRNAs) can modulate multiple gene transcripts including possibly more than one immune checkpoint and could be exploited as immune therapeutics.

METHODS

Using online miRNA targeting prediction algorithms, we searched for miRNAs that were predicted to target both PD-1 and CTLA-4. MiR-138 emerged as a leading candidate. The effects of miR-138 on CTLA-4 and PD-1 expression and function in T cells were determined and the therapeutic effect of intravenous administration of miR-138 was investigated in both immune-competent and -incompetent murine models of GL261 glioma.

RESULTS

Target binding algorithms predicted that miR-138 could bind the 3' untranslated regions of CTLA-4 and PD-1, which was confirmed with luciferase expression assays. Transfection of human CD4+ T cells with miR-138 suppressed expression of CTLA-4, PD-1, and Forkhead box protein 3 (FoxP3) in transfected human CD4+ T cells. In vivo miR-138 treatment of GL261 gliomas in immune-competent mice demonstrated marked tumor regression, a 43% increase in median survival time (P = .011), and an associated decrease in intratumoral FoxP3+ regulatory T cells, CTLA-4, and PD-1 expression. This treatment effect was lost in nude immune-incompetent mice and with depletion of CD4+ or CD8+ T cells, and miR-138 had no suppressive effect on glioma cells when treated directly at physiological in vivo doses.

CONCLUSIONS

MiR-138 exerts anti-glioma efficacy by targeting immune checkpoints which may have rapid translational potential as a novel immunotherapeutic agent.

Checkpoint inhibitors in bladder and renal cancers: results and perspectives

The field of immunotherapy in urinary malignancy is expanding in several directions and checkpoint inhibitors are leading the way. The aim of this report is to highlight the efficacy and safety profile of the two classes of molecules, anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed death receptor-1/programmed death ligand type 1, that are under investigation and represent potential candidates to be used in the near future for the management of bladder and renal cell cancer. The preliminary results as well as the future perspectives of this novel immunotherapy are analyzed. Novel immune checkpoint targets are reviewed as well.

CD4 T cell knockout does not protect against kidney injury and worsens cancer

Most previous studies of cisplatin-induced acute kidney injury (AKI) have been in models of acute, high-dose cisplatin administration that leads to mortality in non-tumor-bearing mice. The aim of the study was to determine whether CD4 T cell knockout protects against AKI and cancer in a clinically relevant model of low-dose cisplatin-induced AKI in mice with cancer. Kidney function, serum neutrophil gelatinase-associated lipocalin (NGAL), acute tubular necrosis (ATN), and tubular apoptosis score were the same in wild-type and CD4 -/- mice with AKI. The lack of protection against AKI in CD4 -/- mice was associated with an increase in extracellular signal-regulated kinase (ERK), p38, CXCL1, and TNF-α, mediators of AKI and fibrosis, in both cisplatin-treated CD4 -/- mice and wild-type mice. The lack of protection was independent of the presence of cancer or not. Tumor size was double, and cisplatin had an impaired therapeutic effect on the tumors in CD4 -/- vs. wild-type mice. Mice depleted of CD4 T cells using the GK1.5 antibody were not protected against AKI and had larger tumors and lesser response to cisplatin. In summary, in a clinically relevant model of cisplatin-induced AKI in mice with cancer, (1) CD4 -/- mice were not protected against AKI; (2) ERK, p38, CXCL1, and TNF-α, known mediators of AKI, and interstitial fibrosis were increased in CD4 -/- kidneys; and (3) CD4 -/- mice had faster tumor growth and an impaired therapeutic effect of cisplatin on the tumors. The data warns against the use of CD4 T cell inhibition to attenuate cisplatin-induced AKI in patients with cancer.

KEY MESSAGE

A clinically relevant low-dose cisplatin model of AKI in mice with cancer was used. CD4 -/- mice were not functionally or histologically protected against AKI. CD4 -/- mice had faster tumor growth. CD4 -/- mice had an impaired therapeutic effect of cisplatin on the tumors. Mice depleted of CD4 T cells were not protected against AKI and had larger tumors.

Immune checkpoint blockade: Releasing the brake towards hematological malignancies

Tumor cells utilize co-inhibitory molecules to avoid host immune destruction. Checkpoint blockade has emerged as a promising approach to treat cancer by restoring T cell effector function and breaking a tumor permissive microenvironment. Patients with hematological malignancies often have immune dysregulation, thus the role of checkpoint blockade in treatment of these neoplasms is particularly intriguing. In early trials, antibodies targeting cytotoxic T lymphocyte antigen 4 (CTLA-4) or the programmed death 1 (PD-1) signaling pathway have displayed significant efficacy with minimal toxicity in patients with relapsed and refractory hematological neoplasms. In this review, we provide evidence of dysregulation of CTLA-4 and PD-1/PD-Ls in the context of several major types of hematological neoplasms and summarize relevant clinical practice points for checkpoint blockade. The preclinical rationale and preliminary clinical data of potential combination approaches designed to optimize checkpoint antagonists are well presented.

Risk of gastrointestinal complications in cancer patients treated with immune checkpoint inhibitors: a meta-analysis

AIM

We performed a meta-analysis of the risk of selected gastrointestinal toxicities associated with immune checkpoint inhibitors.

PATIENTS & METHODS

Eligible studies included randomized trials of patients with solid tumors on ipilimumab, nivolumab, pembrolizumab, tremelimumab, pidilizumab and atezolizumab, describing events of diarrhea, vomiting or colitis.

RESULTS

After exclusion of ineligible studies, a total of ten clinical trials were considered eligible for the meta-analysis. The relative risk of all-grade diarrhea, vomiting and colitis was 1.64 (95% CI: 1.19-2.26; p = 0.002), 0.72 (95% CI: 0.49-1.07; p = 0.1), 10.35 (95% CI: 5.78-18.53; p < 0.00001), respectively.

CONCLUSION

Our meta-analysis has demonstrated that immune checkpoint inhibitors are associated with a significantly increased risk of all grade and high-grade colitis.

Strategies and Advancements in Harnessing the Immune System for Gastric Cancer Immunotherapy

In cancer biology, cells and molecules that form the fundamental components of the tumor microenvironment play a major role in tumor initiation, and progression as well as responses to therapy. Therapeutic approaches that would enable and harness the immune system to target tumor cells mark the future of anticancer therapy as it could induce an immunological memory specific to the tumor type and further enhance tumor regression and relapse-free survival in cancer patients. Gastric cancer is one of the leading causes of cancer-related mortalities that has a modest survival benefit from existing treatment options. The advent of immunotherapy presents us with new approaches in gastric cancer treatment where adaptive cell therapies, cancer vaccines, and antibody therapies have all been used with promising outcomes. In this paper, we review the current advances and prospects in the gastric cancer immunotherapy. Special focus is laid on new strategies and clinical trials that attempt to enhance the efficacy of various immunotherapeutic modalities in gastric cancer.

Predictive factors for immunotherapy in melanoma

Immunotherapy has emerged as an exciting strategy for cancer treatment. Therapeutic blockade of immune checkpoint regulators favors the ability of T cell responses to increase anti-tumor immunity. The cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death-1 (PD-1) are two T cell-inhibitory receptors with independent mechanisms of action. Immune checkpoint inhibitors targeting either CTLA-4, PD-1 or its ligand PD-L1 are currently yielding promising results in terms of efficacy in several clinical studies with melanoma patients and are being developed and tested as immunotherapy agents for multiple cancer types. To date, no reliable predictors of activity and efficacy of immunotherapy have yet been identified or validated. Even so, determining which patients derive clinical benefit from immune checkpoint agents remains an important clinical question and efforts to identify predictive markers of response are ongoing. This article reviews the current potential predictive factors for CTLA-4 and PD-1/PD-L1 immune checkpoints inhibitors in melanoma.

Signaling pathway and dysregulation of PD1 and its ligands in lymphoid malignancies

Tumor cells evade immune destruction, at least partially, by upregulating inhibitory signals to limit effector T cell activation. Programmed death 1 (PD-1) is one of the most critical co-inhibitory molecules limiting the T-cell antitumor response. PD-1 and its ligands, PD-L1 and PD-L2, are overexpressed by various types of tumors as well as reactive cells in the tumor microenvironment. A growing body of evidence has shown the clinical efficiency and minimal toxicity of PD-1 pathway inhibitors in patients with solid tumors, but the role of these inhibitors in lymphoid malignancies is much less well studied. In this review, we analyze the pathologic role of the PD-1 pathway in most common lymphoid malignancies and we organize the clinical data from clinical trials of PD-1 pathway inhibitors. Several anti-PD-1 regimens have shown encouraging therapeutic effects in patients with relapsed or refractory Hodgkin lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma. Additional progress is needed to foster an improved understanding of the role of anti-PD-1 therapy in reconstituting antitumor immunity in patients with lymphoid malignancies. Upcoming trials will explore the clinical efficiency of combining PD-1 pathway inhibitors and various agents with diverse mechanisms of action and create more therapeutic possibilities for afflicted patients.

Emerging targets for combination therapy in melanomas

Cutaneous melanomas are often difficult to treat when diagnosed in advanced stages. Melanoma cells adapt to survive in extreme environmental conditions and are among the tumors with larger genomic instability. Here we discuss some intrinsic and extrinsic mechanisms of resistance of melanoma cells to both conventional and target therapies, such as autophagy, adaptation to endoplasmic reticulum stress, metabolic reprogramming, mechanisms of tumor repopulation and the role of extracellular vesicles in this later phenomenon. These biological processes are potentially targetable and thus provide a platform for research and discovery of new drugs for combination therapy to manage melanoma patient treatment.

Clinacanthus nutans (Burm. f.) Lindau Ethanol Extract Inhibits Hepatoma in Mice through Upregulation of the Immune Response

Clinacanthans nutans (Burm. f.) Lindau is a popular medicinal vegetable in Southern Asia, and its extracts have displayed significant anti-proliferative effects on cancer cells in vitro. However, the underlying mechanism for this effect has yet to be established. This study investigated the antitumor and immunomodulatory activity of C. nutans (Burm. f.) Lindau 30% ethanol extract (CN30) in vivo. CN30 was prepared and its main components were identified using high-performance liquid chromatography (HPLC) and mass spectrometry (LC/MS/MS). CN30 had a significant inhibitory effect on tumor volume and weight. Hematoxylin and eosin (H & E) staining and TUNEL assay revealed that hepatoma cells underwent significant apoptosis with CN30 treatment, while expression levels of proliferation markers PCNA and p-AKT were significantly decreased when treated with low or high doses of CN30 treatment. Western blot analysis of PAPR, caspase-3, BAX, and Bcl2 also showed that CN30 induced apoptosis in hepatoma cells. Furthermore, intracellular staining analysis showed that CN30 treatment increased the number of IFN-γ⁺ T cells and decreased the number of IL-4⁺ T cells. Serum IFN-γ and interleukin-2 levels also significantly improved. Our findings indicated that CN30 demonstrated antitumor properties by up-regulating the immune response, and warrants further evaluation as a potential therapeutic agent for the treatment and prevention of cancers.

Risk of elevated transaminases in cancer patients treated with immune checkpoint inhibitors: a meta-analysis

BACKGROUND

This meta-analysis has been conducted to determine the risk of elevated transaminases associated with immune checkpoint inhibitors use in patients with cancer.

METHODS

Studies eligible for our analysis included randomized Phase II and III trials of patients with cancer on ipilimumab, nivolumab, pembrolizumab, tremelimumab and pidilizumab, which describe events of elevated transaminases [alanine aminotransferase (ALT) and aspartate aminotransferase (AST)].

RESULTS

Initial database search revealed 210 relevant citations. After excluding noneligible studies, 10 trials were considered eligible for the quantitative synthesis. The RR of all-grade elevated ALT and AST was 2.36 (95% CI 1.20-4.66; p = 0.01) and 1.53 (95% CI 0.73-3.22; p = 0.26), respectively, whereas for high-grade elevated ALT and AST, it was 11.27 (95% CI 5.38-23.63; p < 0.0001) and 4.9 (95% CI 2.97-8.09; p < 0.0001), respectively.

CONCLUSIONS

Our study has shown that the use of immune checkpoint inhibitors has a causal relationship to an increased risk of high-grade elevated ALT and AST. Clinicians using these agents should be attentive of this risk.

PD-L1 expression and prognostic impact in glioblastoma

BACKGROUND

Therapeutic targeting of the immune checkpoints cytotoxic T-lymphocyte-associated molecule-4 (CTLA-4) and PD-1/PD-L1 has demonstrated tumor regression in clinical trials, and phase 2 trials are ongoing in glioblastoma (GBM). Previous reports have suggested that responses are more frequent in patients with tumors that express PD-L1; however, this has been disputed. At issue is the validation of PD-L1 biomarker assays and prognostic impact.

METHODS

Using immunohistochemical analysis, we measured the incidence of PD-L1 expression in 94 patients with GBM. We categorized our results according to the total number of PD-L1-expressing cells within the GBMs and then validated this finding in ex vivo GBM flow cytometry with further analysis of the T cell populations. We then evaluated the association between PD-L1 expression and median survival time using the protein expression datasets and mRNA from The Cancer Genome Atlas.

RESULTS

The median percentage of PD-L1-expressing cells in GBM by cell surface staining is 2.77% (range: 0%-86.6%; n = 92), which is similar to the percentage found by ex vivo flow cytometry. The majority of GBM patients (61%) had tumors with at least 1% or more PD-L1-positive cells, and 38% had at least 5% or greater PD-L1 expression. PD-L1 is commonly expressed on the GBM-infiltrating T cells. Expression of both PD-L1 and PD-1 are negative prognosticators for GBM outcome.

CONCLUSIONS

The incidence of PD-L1 expression in GBM patients is frequent but is confined to a minority subpopulation, similar to other malignancies that have been profiled for PD-L1 expression. Higher expression of PD-L1 is correlated with worse outcome.

Classifying Cancers Based on T-cell Infiltration and PD-L1

Cancer immunotherapy may become a major treatment backbone in many cancers over the next decade. There are numerous immune cell types found in cancers and many components of an immune reaction to cancer. Thus, the tumor has many strategies to evade an immune response. It has been proposed that four different types of tumor microenvironment exist based on the presence or absence of tumor-infiltrating lymphocytes and programmed death-ligand 1 (PD-L1) expression. We review this stratification and the latest in a series of results that shed light on new approaches for rationally designing ideal combination cancer therapies based on tumor immunology.

Risk of cutaneous toxicities in patients with solid tumors treated with immune checkpoint inhibitors: a meta-analysis

BACKGROUND

We performed a meta-analysis of the risk of cutaneous toxicities associated with immune checkpoint inhibitors.

METHODS

Eligible studies included randomized trials of patients with solid tumors on immune checkpoint inhibitors (ipilimumab, nivolumab, tremelimumab, pidlizumab and pembrolizumab); describing events of rash, vitiligo and pruritus.

RESULTS

A total of nine clinical trials were considered eligible for the meta-analysis. The relative risk of all-grade rash, vitiligo and pruritus was 4.06 (95% CI: 3.35-4.91; p < 0.0001), 16.3 (95% CI: 3.21-82.8; p = 0.0008) and 3.4 (95% CI: 2.24-5.16; p < 0.00001), respectively.

CONCLUSION

Our meta-analysis demonstrates that immune checkpoint inhibitors are associated with an increased risk of all grade skin rash, vitiligo and pruritus. Clinicians should perform regular clinical cutaneous monitoring.

Repeated PD-1/PD-L1 monoclonal antibody administration induces fatal xenogeneic hypersensitivity reactions in a murine model of breast cancer

Monoclonal antibodies (mAbs) targeting coinhibitory molecules such as PD-1, PD-L1 and CTLA-4 are increasingly used as targets of therapeutic intervention against cancer. While these targets have led to a critical paradigm shift in treatments for cancer, these approaches are also plagued with limitations owing to cancer immune evasion mechanisms and adverse toxicities associated with continuous treatment. It has been difficult to reproduce and develop interventions to these limitations preclinically due to poor reagent efficacy and reagent xenogenecity not seen in human trials. In this study, we investigated adverse effects of repeated administration of PD-1 and PD-L1 mAbs in the murine 4T1 mammary carcinoma model. We observed rapid and fatal hypersensitivity reactions in tumor bearing mice within 30-60 min after 4-5 administrations of PD-L1 or PD-1 mAb but not CTLA-4 antibody treatment. These events occurred only in mice bearing the highly inflammatory 4T1 tumor and did not occur in mice bearing non-inflammatory tumors. We observed that mortality was associated with systemic accumulation of IgG1 antibodies, antibodies specific to the PD-1 mAb, and accumulation of Gr-1^high neutrophils in lungs which have been implicated in the IgG mediated pathway of anaphylaxis. Anti-PD-1 associated toxicities were alleviated when PD-1 blockade was combined with the therapeutic HSP90 inhibitor, ganetespib, which impaired immune responses toward the xenogeneic PD-1 mAb. This study highlights a previously uncharacterized fatal hypersensitivity exacerbated by the PD-1/PD-L1 axis in the broadly used 4T1 tumor model as well as an interesting relationship between this particular class of checkpoint blockade and tumor-dependent immunomodulation.